To perform a sentinel node biopsy an imaging agent is injected around the tumor allowing the surgeon to find the node by using a hand-held gamma probe. Scatter radiation from the injection site can inhibit the ability to identify a sentinel node and often, radioactivity disseminates into multiple nodes causing more than the necessary number of nodes to be removed. The standard agent, Tc-Sulfur Colloid does not have these problems. An ideal sentinel node imaging agent would exhibit rapid clearance from the injection site and sustained uptake by the sentinel node. Technetium-99m-labeled DTPA-mannosyl-dextran is a new radiotracer that has been shown in a Phase I Clinical Trial to have these properties. The purpose of this study is to translate this laboratory data into the clinical setting via a phase II clinical trial. The FDA Guidance for Industry states that the purpose of a Phase II clinical trial of a medical imaging agent is: 1) to optimize the imaging protocol, 2) to obtain preliminary evidence of efficacy, and 3) to continue the assessment of its biological safety. Therefore, this project will have three specific aims. Data for Specific Aim One will include injection site retention and injection site localization at 3 and 16 hours post administration of our new receptor-binding radiotracer. We will test the hypothesis that our new agent provides superior detection properties at 16 hours post administration. Data for Specific Aim Two will include injection site retention and injection site localization of filtered Tc-sulfur colloid. We will test the hypothesis that our new agent provides superior imaging and detection properties compared to the current radiotracer used for sentinel node detection. Data for Specific Aim Three will include subject observation and clinical laboratory tests obtained before and after administration of our new agent. We will test the hypothesis that our new agent does not alter any clinical laboratory test results.